Should You Stop Blood Thinners Before Surgery?

A new guideline from the American Academy of Neurology will help people who take blood thinners decide whether or not to take them during surgery or other medical procedures. The guideline is published in the May 28, 2013, print issue of Neurology, the medical journal of the American Academy of Neurology.

People who have had a stroke often take blood thinners such as aspirin or warfarin to prevent another stroke. Blood thinners, or anticlotting drugs, are also used to prevent a first stroke in people with atrial fibrillation, an irregular or fast heartbeat. Blood thinners can prevent blood clots from forming that can cause strokes. However, these drugs also can increase the risk of bleeding. Increased bleeding is especially a concern when someone is having a procedure or operation.

"There may be millions of Americans taking anticlotting drugs to prevent a stroke," said guideline author Melissa J. Armstrong, MD, an assistant professor of neurology with the University of Maryland School of Medicine in Baltimore. "For every dental procedure, minor medical procedure or surgery these people plan to have, they should work with their doctors to decide if these drugs should be continued to maintain stroke prevention efforts or temporarily stopped to lower the risk of bleeding with the procedure."

The risk of bleeding varies depending on the procedure, according to the guideline, which was developed by reviewing all available evidence to date. For many minor procedures, including dental procedures, the bleeding risk from continuing blood thinners is fairly small.

For some other procedures, the risk of bleeding may be higher when blood thinners are continued. Examples are certain hip and colon procedures.

"This guideline helps patients and doctors know what the evidence tells us about these different risks," Armstrong said. "A person's health history and preferred course of action are also important to discuss when making this decision."

Most of the studies on bleeding risks from blood thinners during procedures focus on aspirin and warfarin. Armstrong said more studies are needed to understand the bleeding risks of other blood thinners, such as clopidogrel and aspirin plus dipyridamole, as well as new anticoagulants such as dabigatran, rivaroxaban or apixaban, during or before procedures.

Some people take blood thinners for heart problems. The guideline did not review evidence for people with heart problems other than atrial fibrillation.